Table 1.

Amino acid sequence at the β2-α2 loop of PrP^C and in vivo barrier to prion conversion

PrP construct expressed in transgenic mice	Primary sequence 167–175	Secondary structure of β2-α2 loop	Transmission barrier to RML mouse prions	Transmission barrier to CWD deer prions
MoPrP	DQYSNQNNF	Disordered	No	Yes
MoPrP167S	SQYSNQNNF	Ordered, rigid	No	Yes
MoPrP170N,174Ta	DQYNNQNTF	Ordered, rigid	Yes	Yesb
CerPrPa	DQYNNQNTF	Ordered, rigid	Yes	No

^aThe transmission barriers were described previously (24, 39).

^bAll mice developed prion disease <400 d after inoculation, whereas mice expressing MoPrP or MoPrP^167S required >400 d after inoculation to develop CWD-induced prion disease or resisted CWD infection.